Composition Dependence of the Photoluminescence Spectra of Zn 1−x Cd x Ga 2 Se 4 Crystals
Chang-Dae Kim ∗
Department of Physics, Mokpo National University, Mokpo 534-729, Korea (Received 12 July 2014 : revised 29 July 2014 : accepted 29 July 2014)
The composition dependence of the photoluminescence spectra of Zn
1−xCd
xGa
2Se
4semiconduc- tor crystals that had been prepared by using a melting technique was investigated in the composition region of 0.0 ≤ x ≤ 1.0. The photoluminescence spectra at 12 K of Zn
1−xCd
xGa
2Se
4showed an emission band (A-peak) of 1.83 eV (678 nm) for x = 0.0 (ZnGa
2Se
4) and an emission band (B- peak) of 2.13 eV (582 nm) for x = 1.0 (CdGa
2Se
4). For compositions of 0.4 ≤ x ≤ 0.8, a new emission band (C-peak) was observed along with the A- and the B-peaks. The new emission band was observed at 1.78 eV (697 nm) for the crystals with x = 0.4 and appeared to be shifted to higher energies with increasing x. We suggest a simple energy-level scheme for Zn
1−xCd
xGa
2Se
4(x = 0.4) on the basis of the deep levels obtained by using thermally-stimulated-current measurements for ZnGa
2Se
4and CdGa
2Se
4in our earlier studies The energy-level scheme allows us to assign the emission band observed for x = 0.4.
PACS numbers: 78.20.-e, 78.55.-m
Keywords: Zn
1−xCd
xGa
2Se
4, Photoluminescence, Deep levels
Zn 1−x Cd x Ga 2 Se 4 + s ÇX N Ë; c" e8 ý ° Ë Ñ® o° Ë Ñ z ð ² â ì È8 ý ºV R Ë8 ýÇ X ØV R Ë ¤V R Ë
» ç ¡6 0 ∗
3 l
q í@ / < Æ § õ < Æ@ / < Æ Ó ü t o < Æõ , 3 l q í 534-729
(2014¸ 7 Z 4 12{ 9 ~ Ã Î6 £ §, 2014¸ 7 Z 4 29{ 9 Ã º& ñ : r ~ Ã Î6 £ §, 2014¸ 7 Z 4 29{ 9 > F S X & ñ )
Zn
1−xCd
xGa
2Se
4ì ø Í ¸^ & ñ ` ¦ 0.0 ≤ x ≤ 1.0 ¸$ í % ò % i \ " f 6 xÖ 6 xZ O Ü ¼ Ð $ í © ¦, s ¸$ í % ò
%
i \ " f ¸$ í q x_ o\ É r F g µ 1 Ï F g : £ ¤$ í _ ¸$ í _ > r$ í ` ¦ ¸ % i . Zn
1−xCd
xGa
2Se
4& ñ _ 12 K \ " f_ F g µ 1 Ï F g : £ ¤$ í É r x = 0.0 ZnGa
2Se
4â Ä º 1.83 eV (678 nm)% ò % i \ " f ; ¤ V , É r µ 1 Ï F g x ß ¼ (A- x ß ¼) ' a8 £ ¤ ÷ &% 3 ¦, x = 1.0 CdGa
2Se
4\ " f H 2.13 eV (582 nm)% ò % i \ " f ; ¤ V , É r µ 1 Ï F g x ß ¼ (B- x ß ¼) ' a8 £ ¤ ÷ &% 3 . ¢ ¸ô Ç 0.4 ≤ x ≤ 0.8 ¸$ í % ò % i \ " f H A- x ß ¼, B-x ß ¼ü < < Êa D h Ðî r µ 1 Ï F g x ß
¼ (C-x ß ¼) ' a8 £ ¤ ÷ &% 3 . s D h Ðî r µ 1 Ï F g x ß ¼ H x = 0.4 & ñ \ " f H 1.78 eV (697 nm) % ò % i \
"
f ' a8 £ ¤ ÷ &% 3 Ü ¼ 9, x 7 £ x < Ê\ Z } É r \ -t 8 £ ¤ Ü ¼ Ð s 1 l x ÷ &# Q ' a8 £ ¤ ÷ &% 3 . Ä ºo H ZnGa
2Se
4ü <
CdGa
2Se
4_ \ P F G À Ó 8 £ ¤& ñ \ _ ô Ç U · É r ï r 0 A\ @ /ô Ç s _ ½ ¨ õ \ ¦ ½ ÓÜ ¼ Ð x = 0.4 Zn
1−xCd
xGa
2Se
4& ñ _ \ -t ½ × ¼ ¸+ þ A` ¦ ] jr % i Ü ¼ 9, s ÐÂ Ò' x = 0.4 & ñ \ " f ' a8 £ ¤ ) a D h
Ðî r µ 1 Ï F g x ß ¼ (C-x ß ¼)_ µ 1 Ï F g s \ ¦ [ O " î % i .
PACS numbers: 78.20.-e, 78.55.-m
Keywords: Zn
1−xCd
xGa
2Se
4, F g µ 1 Ï F g, U · É r ï r 0 A
∗